CHAPTER 3 ELECTRICITY AND CIRCIUTS
Electricity makes our life easier. Imagine how difficult our life would be without electricity.
Some gadgets which run on electricity are plugged into sockets. But there are some gadgets which do not require being plugged in. these gadgets use electric cells to work.
In simple terms, electric current is the flow of electricity. Current flows from the positive terminal to the negative terminal of the cell. We’ll learn about the electric cells later.
When various components such as bulb, cell and switch are arranged in a manner that current can flow through it, the arrangement is called an electric circuit. When the switch is closed and current can pass through the circuit, it is called a closed circuit. If the switch is off and the current does not flow in the circuit, it is called an open circuit.
COMPONENTS OF AN ELECTRIC CIRCUIT
An electric cell uses chemicals stored inside it to produce electricity. There is a small metal cap on one side and a metal disc on the other side. The metal cap is the positive terminal and the metal disc is the negative terminal. The chemicals inside the cell produce electricity and when they get used up, the cell stops working.
A bulb is nothing but a filament enclosed in a glass case. A filament is a thin wire that gives off light. A bulb also has two terminals. An electric bulb glows when electric current passes through it.
A switch is used to either complete a circuit or to break it. When the switch is on, the circuit is complete and current flows through it. When the switch is off, the circuit is incomplete and current does not flow through it.
Conductor is a material that allows electric current to pass through it. E.g.: Metals
Insulator is a material that does not allow electric current to pass through it. E.g.: Wood, air